When I first saw the OM7s response, I thought it couldn't possibly be true.

Unless I'm reading them wrong here are some comparisons (2kHz up range):

OM7 @ 30º off axis = -9dB | SM58 @ 30º off axis = 0dB

OM7 @ 60º off axis = -18dB | SM58 @ 60º off axis = -5dB

OM7 @ 90º off axis = -21dB | SM58 @ 90º off axis = -5 to -10dB

and so on........

Whilst I'm still not sure the OM7 specs are indeed true - they are born out on stage.

And, by the way, the argument about attenuating an SM58 to match doesn't bear up - you compare the microphones with the gain set appropriately for the source and under those circumstances the OM7 provides more gain before feedback.

Not arguing Bob, don't have one nor the place to try it. I was just looking for the "Amazing New Principle" that gave the OM7 its feedback immunity and found there isn't one. It is a very low sensitivity mic that requires very close use* and necessitates the singer gives it some. The tighter polar pattern helps as well.

Not knocking the OM7! Super mic I am sure, just works by principles known for a century.

Attenuating a "lesser" microphone would then require very close working. Even a 58 could overload some mic pres in such a situation with some singers? (Tom Jones had a bit of a reputation as a mic masher!) I think my statement "mics are but one factor in feedback control" still stands? If the singer does not work it correctly, even the OM7 will squeal!

*The old noise cancelling Reslo used in F1 pits worked on a similar principle in that it required a very close technique and had a guard ring so as to get the mouth in the dead right position (yes, I know it also exploited the proximity effect and EQ'ed the pips out of the signal!)

ef37a wrote:One wonders how an SM58 might perform with a -6dB slug in the cable?

Exactly the same, other than the fact you'll need to add back the 6dB elsewhere in the signal path. After all, gain is gain, no more and no less, wherever it is in the signal path.

Except that if you left the gain as was the singer has to work harder. One of the abiding principles of good feedback control (or indeed low noise amplification) is...Get the biggest signal you can. In this case the acoustic output of the gob.

True, an increase in the signal/background noise ratio is always welcome and benefits gain before feedback. However a high output mic and a low output mic with the same polar pattern, if the mixing desk gain is set up so that both signal levels going through the desk are the same , then there will be the same gain before feedback level for both mics.

A higher output mic signal will result in less mixer gain needed, which can result in a higher signal/electrical noise ratio, but doesn't affect feedback resistance as the overall system gain is exactly the same. 20dB (mic) + 60dB (preamp gain) = 80dB, the same as if if were 25dB +55dB (figures for example purposes only).

The only way to really increase gain before feedback is to have a much tighter polar pattern. Ideally you want a mic where only the sound in front of the mic is captured, but this has practical and sonic limitations. So you end up with a mic like the OM7 which has a very tight, very directional, pickup pattern with a lot of rejection to the sides and rear. But the result is a mic whose output falls off very rapidly if you move your mouth to the side by a cm or so. So it needs to be kept right up against the mouth just to make sure the vocals don't sound like Norman Collier. https://youtu.be/AYpQyJ_bTiw

ef37a wrote:...I was just looking for the "Amazing New Principle" that gave the OM7 its feedback immunity and found there isn't one. It is a very low sensitivity mic that requires very close use* and necessitates the singer gives it some. The tighter polar pattern helps as well.

Not knocking the OM7! Super mic I am sure, just works by principles known for a century.

Attenuating a "lesser" microphone would then require very close working. Even a 58 could overload some mic pres in such a situation with some singers?

I think my statement "mics are but one factor in feedback control" still stands?

All kind of correct (apart from your artistic use of question marks, but my daughter tells me I must own my own pedantry and not judge).

As a regular user I concur with Bob B's observations and conclusions. I don't think Bob is suggesting there is any magic ingredient but rather that Audix have prioritised GBF in response to the modern stage environment and have manipulated the existing variables very successfully.

As mentioned before I like to turn the OM-7 input gain up and sing gently. If you are suggesting that this would compromise the GBF properties, it doesn't (in comparison with '58, e935, etc.).

It also sounds good.

[edit]I would qualify the suggestion that a singer needs to be in direct contact with the OM-7 to be effective, that's an exaggeration. The range is dramatically reduced but normal rules regarding movement on and off the mic still apply.

In real life, if you've probably chosen the OM-7 it's because the stage is loud and in those cases folks are belting into the mic and performance is less nuanced.

ef37a wrote:I was just looking for the "Amazing New Principle" that gave the OM7 its feedback immunity and found there isn't one.

Of course there's no " Amazing New Principle" - but Audix have engineered a microphone which has managed to attenuate pick-up from the sides and rear like no other microphone that I'm aware of, as evidenced in their published data and my actual experience. Did you analyse the polar responses?

I'm really surprised you're holding out on this one Dave, given you haven't tried one. Round here, we like to give good advice when it's asked for, don't we?

When I'm asked what stage vocal microphone are best for feedback rejection - I'll answer the OM7 based on my analysis of the data provided and practical experience. BUT as noted, it's a compromise and requires absolute 'nasal hair trapped in the grill' technique.

ef37a wrote:I was just looking for the "Amazing New Principle" that gave the OM7 its feedback immunity and found there isn't one. It is a very low sensitivity mic that requires very close use* and necessitates the singer gives it some. The tighter polar pattern helps as well.

I think you have that the wrong way around Dave. It's the very tight polar pattern that gives it the feedback immunity, and the lower sensitivity helps as well...

Any mic can be operated with a low sensitivity... But what makes a real difference is how well the mic rejects unwanted sound from directions other than the vocalist -- and that's where the very tight pattern of the OM7 really makes such a big difference.

Attenuating a "lesser" microphone would then require very close working.

Of course, but even then if there are high levels of foldback/spill on stage, it would still start to feedback before the OM7 because it is much more sensitive to sounds from the sides...

If the singer does not work it correctly, even the OM7 will squeal!

Obviously... but they'd have to try a lot harder than with an SM58... and that's what matters! :-)

Peter H wrote:If I were the OP, I'd get an SM58 (or similar) AND an E945 (or similar?) and compare. There are so many idiosyncratic factors involved in live gigs, and that's before even considering the vocal channel/EQ etc. and the speakers.

The OP already uses an SM58 IIRC.

MOF wrote:

Looking at the OP's (lip-synched) showreel he appears to slightly cup the mic basket which, as we know, is almost guaranteed to make a 58 feed back. Am I right in thinking that the effect would be even worse with a super/hyper-Cardioid?

Doing this makes the mic’ go into an Omni’ pickup pattern so I don’t think it will be any worse with a hyper-cardioid mic’ but clearly no good at feedback rejection.

Hugh Robjohns wrote:It might be interesting to compare the OM7 with other nominally hyper-cardioid stage mics in a practical situation. If you (or anyone else) feel so inclined I'd love to see the results.

H

We ran tests a few years back to replicate a fairly typical stage scenario where a lead vocalist in a rock band would be requiring high gain from a single monitor. I don’t think we repeated the test with dual monitors. This was done in a 400 seat theatre with sensible positioning of FOH speakers, so potential feedback was only from the monitor.

From memory the hypercardioid mics we tested were:

Beta58RE510KMS105E845M69M88Possibly ND967OM7

I wouldn’t describe it as a scientific test! Channel and monitor EQ were flat. For each mic an optimum gain was set to deliver the same level for the vocalist and then the gain in monitors was increased until feedback occurred and compared. The OM7 won out by a long shot and this has since been proven ‘in the field’.

I’m not saying the OM7 is the best mic, I tend to grab an M69, M201 or KMS105 first up (dependent on voice and genre), but it is the most feedback resistant I’ve come across.

I looked up those mic specs. As best I could find, here are the nominal polar patterns, H being hypercardioid and S supercardioid. So not really a test of hypercardioids.

And of course it depends on the angle from the mic's axis at which the monitor is placed. At some angles you would expect the supercardioids generally to have better feedback resistance, and at others, the hypercardioids better. And of course depending on the frequency...

...Sennheiser e835 is not bad, but I'd prefer to spend the extra and get the e935.

Finally had a couple of gigs which replicate the scenario described and had the chance to do a little comparing

Gig 1) busy bar, dl1608 into Yamaha dxr12, one of the dxrs is right on top of us (gtr/vox, flute [Audix om5]). I put my current first choice Senn e935 up but as the room fills up and b/g noise increases I increase our level higher than I had anticipated would be necessary. Senn is now getting a bit muddy and resonant but rather than deal with that during the break I swapped over to the Lewitt 550 (requiring a little more input gain) and with tweaking all is clear and sits well in the mix. Mids are well defined but articulation is sufficiently detailed.

Gig 2) busy bar, dl1608 into EV powered 12"s (didn't get model number, single sided wedge shape, recently installed). one speaker within 6' of the vocal mic. Playing with a piezo equipped fiddle player this time who sometimes struggles with feedback at around 600hz in this venue (wouldn't if it was a regular gig of mine). Went for the Lewitt for the first set but there is definite resonant "phasiness" around the 1khz area. loathe to pull too much out as vox will eventually disappear. Headroom is non existent even at relatively inoffensive volume levels. I swap the the Senn.

Body and detail suddenly super- present. I'm able to sit back on the mic and sing much more gently without issues. significant extra headroom.

Conclusion, Lewitt is great for shouting in a busy mix but is not particularly impressive regarding feedback rejection. Senn is fuller, more detailed but will not cut through a busy mix quite so well. responds better to eq and is worth the tweaking.

Interesting! I guess it suffer from the usual issue of hypercardioids - that you must sing right in the mic front?

I use an HC mic (an old AKG D-something) and it took quite a while to learn to come back from the mic front after looking at guitar. In the last couple years I've started liking SM58s better and better live just because they make my life so much easier.